<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- 准备好一个“容器” -->
	<div id="test"></div>
	
	<!-- 引入react核心库 -->
	<script type="text/javascript" src="../js/react.development.js"></script>
	<!-- 引入react-dom，用于支持react操作DOM -->
	<script type="text/javascript" src="../js/react-dom.development.js"></script>
	<!-- 引入babel，用于将jsx转为js -->
	<script type="text/javascript" src="../js/babel.min.js"></script>

    <script type="text/babel">
        //创建组件
		//生命周期回调函数 <=> 生命周期钩子函数 <=> 生命周期函数 <=> 生命周期钩子
        class Life extends React.Component {

            state = {
                opacity : 1
            }

            death = () => {
                //卸载组件
                ReactDOM.unmountComponentAtNode(document.getElementById('test'));
            }

            //挂载组件完毕
            componentDidMount() {
                this.timer = setInterval(() => {
                    //获取原始状态
                    let {opacity} = this.state;
                    //设置状态值
                    if(opacity <= 0) {
                        opacity = 1;
                    } else {
                        opacity -= 0.1;
                    }
                    //设置新的透明度
                    this.setState({
                        opacity
                    })
                }, 200);
            }

            //组件将要卸载
            componentWillUnmount() {
                //清除定时器
                clearInterval(this.timer);
            }

            //初始化渲染、状态更新之后
            render() {
                return (
                    <div>
						<h2 style={{opacity:this.state.opacity}}>React学不会怎么办？</h2>
						<button onClick={this.death}>不活了</button>
					</div>
                )
            }
        }

        //将组件渲染到页面
        ReactDOM.render(<Life/>, document.getElementById('test'));
    </script>
</body>
</html>